Some catalytic properties of ZSM-5, a new shape selective zeolite

Chen, N.Y.; Garwood, W. E.

doi:10.1016/0021-9517(78)90350-0

Cited by 186 publications

(52 citation statements)

References 6 publications

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“…An analysis of the cage effects exhibited by ERItype and AFX-type zeolites [22][23][24][25][26][27][28]30] shows that the adsorption thermodynamics of the n-alkanes is at least as important a constituent of the cage effect as the n-alkane diffusion rate. This highlights a shortcoming in the traditional view of reactant shape selectivity as the unambiguous effect of a zeolite topology on the preferential conversion of the reactant that adsorbs most rapidly in diffusion-limited reactions.…”

Section: Discussionmentioning

confidence: 99%

“…1) [23][24][25]28]. The historic explanation for this phenomenon is that the reactivity decreases due to a strong decrease of the diffusion rate with n-alkane length [23][24][25][26][27][28]. However, this explanation is at variance with the simultaneously reported marked increase in diffusion rate with increasing n-alkane length from n-C 10 to n-C 12 [23][24][25]28,50].…”

Section: Diffusion and Adsorption Combine To Yield A Cage Effect For mentioning

confidence: 99%

“…In principle, these improved-mileage automobiles afforded an adequate response to the high gasoline prices of the 1970s [2]. At the time of for the cage effect have focused exclusively on the effect of zeolite topology on the barrier to adsorption [22][23][24][25][26][27][28][29][30][31]. In this paper we show that the difference in Gibbs free energy level between gas and adsorbed phase (viz.…”

Section: Introductionmentioning

confidence: 99%

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Understanding cage effects in the n-alkane conversion on zeolites

Maesen

Beerdsen

Calero

et al. 2006

Journal of Catalysis

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Molecular simulations are used to provide insight into published catalytic reactivity data for zeolites that exhibit a cage effect, the selective and preferential conversion of short-chain rather than long-chain n-alkanes. This paper demonstrates that understanding cage effects for ERI-, AFX-, and FER-type zeolites requires consideration of four components: (1) adsorption thermodynamics, (2) adsorption kinetics, (3) conversion at the exterior surface of the catalysts, and (4) coke-induced modifications to the pore texture. By breaking down the Gibbs free energy of adsorption into its enthalpic and entropic contributions, we can further elucidate the influence of the zeolite topology on the adsorption of n-alkanes with different hydrocarbon chain lengths. This analysis indicates that zeolite topologies with cages accessible through windows <0.47 nm wide are particularly prone to exhibiting a cage effect, because they impose a high thermodynamic penalty on the adsorption of molecules that are too long to fit comfortably in a single cage. This improved understanding of the cage effect could facilitate its renewed use in commercial practice.  2005 Elsevier Inc. All rights reserved.

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Section: Discussionmentioning

confidence: 99%

Section: Diffusion and Adsorption Combine To Yield A Cage Effect For mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Understanding cage effects in the n-alkane conversion on zeolites

Maesen

Beerdsen

Calero

et al. 2006

Journal of Catalysis

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“…Among the 3 xylene isomers, p-xylene is not thermodynamicaly favored, but its formation is favored because the diffusivity of p-xylene is several orders of magnitude larger than those of m-xylene and o-xylene, as demonstrated by Chen and coworkers (27,28). The product shape selectivity corresponds to the above-mentioned Type II selectivity in heterogeneous reactions.…”

Section: Product Shape Selectivitymentioning

confidence: 89%

Introduction to Shape-Selective Catalysis

Chen

Garcés

Sugi

1999

ACS Symposium Series

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Shape-selective catalysis is important for synthesis of organic chemicals and for processing of petroleum fractions and fuels. This article provides an introductory overview of the principles and applications of shape selective catalysis. It also discusses current areas of research on shape-selective catalysis.According to a recent study conducted jointly by several professional societies and industrial associations summarized in "Technology Vision 2020" report, catalysis is used in making over 60% of the products and accounts for 90% of the manufacturing process in the U.S. chemical industry that generates 7,000 different products (1,2). Governmental studies also indicated that catalytic technologies contributed some 20-30% to gross domestic product in both the U.K. and the U.S. (3). This includes not only chemical industry but also other manufacturing sectors such as petroleum refining industry for making clean transportation fuels, and automobile industry where catalysts are used for control of emissions from exhaust gases.Heterogeneous catalysis plays an important role in hydrocarbon processing, chemicals synthesis, and environmental protection. In 1992 over $1.48 billion worth of catalysts were used in the U.S. chemical and petroleum industries; these catalysts resulted in the production of over $890 billion worth of products, roughly equivalent to 18% of US GNP (4). For example, a single pound of catalyst can easily process 1,200-2000 pounds of gasoline. In 1993, U.S. catalyst sales market was $1.93 billion, with a breakdown including chemicals ($650 million), petroleum, ($665 million), automotive ($570 million), and other industrial catalysts ($50 million) (4). In keeping with the above-mentioned "Technology Vision 2020" report, two major goals for catalysis in the next twenty-five years are accelerating new catalyst development and raising catalyst selectivity approaching 100% (5).Shape-selective catalysis occupies an unique position in manufacturing industries for environmentally benign chemical processing, because it provides specific, desired pathways leading to desired products in hydrocarbon processing and chemicals 4 Corresponding author.

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“…The catalytic properties of the high silica zeolite ZSM-5 have received much attention [70,7]. The initial commercial or near commercial applications reported [7] for ZSM-5 include: a) the isomerization of C8 aromatics to produce isomerically pure xylenes, especially paraxylene for polyester manufacture; b) ethylbenzene synthesis for styrene production; and c) catalytic dewaxing [71].…”

Section: Catalyst Applicationsmentioning

confidence: 99%

Molecular sieve zeolite technology - the first twenty-five years

Flanigen¹

1980

Pure and Applied Chemistry

116

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In twenty-five years molecular sieve zeolites have substantially impacted adsorption and catalytic process technology throughout the chemical process industries; provided timely solutions to energy and environmental problems; and grown to over a hundred million dollar industry worldwide. The evolution in zeolite materials with improved or novel properties has strongly influenced the expansion of their applications, and provided new flexibility in the design of products and processes.

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Some catalytic properties of ZSM-5, a new shape selective zeolite

Cited by 186 publications

References 6 publications

Understanding cage effects in the n-alkane conversion on zeolites

Understanding cage effects in the n-alkane conversion on zeolites

Introduction to Shape-Selective Catalysis

Molecular sieve zeolite technology - the first twenty-five years

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